javascript - 在点击文字之前限制图片上传

Question

一旦用户点击蒙版图像，我们就会显示文件上传对话框框....一旦用户上传图像，我们就会显示“删除图像"文本....

问题:

现在用户可以在点击“删除图片”之前上传另一张图片，但是点击“删除图片”之后，只有用户可以上传另一张图片，因为类似于 link ....

代码笔:https://codepen.io/kidsdial/pen/EJyYZg

fiddle :https://jsfiddle.net/kidsdial1/z61cng7s/1/

下面是代码片段:

var target;
var imageUrl = "https://i.imgur.com/RzEm1WK.png";

// Json - it includes mask image 
let jsonData = {
    "layers": [{
        "x": 10,
        "height": 500,
        "layers": [{
            "x": 20,
            "layers": [{
                    "x": 30,
                    "src": "ax0HVTs.png",
                    "y": 31,
                    "name": "mask_1"
                }

            ],
            "y": 21,
            "name": "user_image_1"
        }],
        "y": 11,
        "width": 500,
        "name": "L1"
    }]
};

$(document).ready(function() {

    // upload image onclick mask image

    $('.container').click(function(e) {

        var res = e.target;
        target = res.id;
        console.log(target);
        if (e.target.getContext) {
            // click only inside Non Transparent part
            var pixel = e.target.getContext('2d').getImageData(e.offsetX, e.offsetY, 1, 1).data;
            if (pixel[3] === 255) {
                setTimeout(() => {
                    $('#fileup').click();
                }, 20);
            }
        }
    });

    // Below code will fetch mask image from json file

    function getAllSrc(layers) {
        let arr = [];
        layers.forEach(layer => {
            if (layer.src) {
                arr.push({
                    src: layer.src,
                    x: layer.x,
                    y: layer.y,
                    name: layer.name
                });
            } else if (layer.layers) {
                let newArr = getAllSrc(layer.layers);
                if (newArr.length > 0) {
                    newArr.forEach(({
                        src,
                        x,
                        y,
                        name
                    }) => {
                        arr.push({
                            src,
                            x: (layer.x + x),
                            y: (layer.y + y),
                            name: (name)
                        });
                    });
                }
            }
        });
        return arr;
    }

    function json(data)

    {
        var width = 0;
        var height = 0;

        let arr = getAllSrc(data.layers);

        let layer1 = data.layers;
        width = layer1[0].width;
        height = layer1[0].height;
        let counter = 0;
        let table = [];

        for (let {
                src,
                x,
                y,
                name
            } of arr) {
            $(".container").css('width', width + "px").css('height', height + "px").addClass('temp');
            if (name.indexOf('mask_') !== -1) {
                var imageUrl1 = imageUrl;
            } else {
                var imageUrl1 = '';
            }
            var mask = $(".container").mask({
			// icon  : 
                imageUrl: imageUrl1,
			// Mask image :
                maskImageUrl: 'https://i.imgur.com/' + src,
                onMaskImageCreate: function(img) {

                    // image positions : 

                    img.css({
                        "position": "absolute",
                        "left": x + "px",
                        "top": y + "px"
                    });

                },
                id: counter
            });
            table.push(mask);
            fileup.onchange = function() {

                let mask2 = table[target];
                const newImageLoadedId = mask2.loadImage(URL.createObjectURL(fileup.files[0]));
                document.getElementById('fileup').value = "";
                
                //  Remove image

                $("<br/><span id=\"" + newImageLoadedId + "\" class=\"remove\">Remove image</span>").insertAfter("#fileup");

                $(".remove").click(function(event) {
                    const canvasId = "canvas#" + event.currentTarget.id;
                    // Delete the image
                    const ctx = $("canvas")[event.currentTarget.id].getContext("2d");
                    ctx.fillStyle = "white"
                    ctx.fillRect(0, 0, 500, 500)
                    // Delete the button
                    $(this).remove();                    
                });

                // Remove image code end here....

            };
            counter++;
        }

    }
    json(jsonData);
}); // end of document ready

// upload image & drag code

(function($) {
    var JQmasks = [];
    $.fn.mask = function(options) {
        // This is the easiest way to have default options.
        var settings = $.extend({
            // These are the defaults.
            maskImageUrl: undefined,
            imageUrl: undefined,
            scale: 1,
            id: new Date().getUTCMilliseconds().toString(),
            x: 0, // image start position
            y: 0, // image start position
            onMaskImageCreate: function(div) {},
        }, options);


        var container = $(this);

        let prevX = 0,
            prevY = 0,
            draggable = false,
            img,
            canvas,
            context,
            image,
            timeout,
            initImage = false,
            startX = settings.x,
            startY = settings.y,
            div;

        container.mousePosition = function(event) {
            return {
                x: event.pageX || event.offsetX,
                y: event.pageY || event.offsetY
            };
        }

        container.selected = function(ev) {
            var pos = container.mousePosition(ev);
            var item = $(".masked-img canvas").filter(function() {
                var offset = $(this).offset()
                var x = pos.x - offset.left;
                var y = pos.y - offset.top;
                var d = this.getContext('2d').getImageData(x, y, 1, 1).data;
                return d[0] > 0
            });

            JQmasks.forEach(function(el) {
                var id = item.length > 0 ? $(item).attr("id") : "";
                if (el.id == id)
                    el.item.enable();
                else el.item.disable();
            });
        };

        container.enable = function() {
            draggable = true;
            $(canvas).attr("active", "true");
            div.css({
                "z-index": 2
            });
        }

        container.disable = function() {
            draggable = false;
            $(canvas).attr("active", "false");
            div.css({
                "z-index": 1
            });
        }

        container.updateStyle = function() {
            return new Promise((resolve, reject) => {
                context.beginPath();
                context.globalCompositeOperation = "source-over";
                image = new Image();
                image.setAttribute('crossOrigin', 'anonymous');
                image.src = settings.maskImageUrl;
                image.onload = function() {
                    canvas.width = image.width;
                    canvas.height = image.height;
                    context.drawImage(image, 0, 0, image.width, image.height);
                    div.css({
                        "width": image.width,
                        "height": image.height
                    });
                    resolve();
                };
            });
        };

        function renderInnerImage() {
            img = new Image();
            img.setAttribute('crossOrigin', 'anonymous');
            img.src = settings.imageUrl;
            img.onload = function() {
                settings.x = settings.x == 0 && initImage ? (canvas.width - (img.width * settings.scale)) / 2 : settings.x;
                settings.y = settings.y == 0 && initImage ? (canvas.height - (img.height * settings.scale)) / 2 : settings.y;
                context.globalCompositeOperation = 'source-atop';
                context.drawImage(img, settings.x, settings.y, img.width * settings.scale, img.height * settings.scale);
                initImage = false;
            };
        }

        // change the draggable image

        container.loadImage = function(imageUrl) {
            console.log("load");
            //if (img)
            // img.remove();
            // reset the code.
            settings.y = startY;
            settings.x = startX;
            prevX = prevY = 0;
            settings.imageUrl = imageUrl;
            initImage = true;
            container.updateStyle().then(renderInnerImage);           
            return settings.id;
        };


        // change the masked Image
        container.loadMaskImage = function(imageUrl, from) {
            canvas = document.createElement("canvas");
            context = canvas.getContext('2d');
            canvas.setAttribute("draggable", "true");
            canvas.setAttribute("id", settings.id);
            settings.maskImageUrl = imageUrl;
            div = $("<div/>", {
                "class": "masked-img"
            }).append(canvas);

            // div.find("canvas").on('touchstart mousedown', function(event)
            div.find("canvas").on('dragstart', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.onDragStart(event);
            });

            div.find("canvas").on('touchend mouseup', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.selected(event);
            });

            div.find("canvas").bind("dragover", container.onDragOver);
            container.append(div);
            if (settings.onMaskImageCreate)
                settings.onMaskImageCreate(div);
            container.loadImage(settings.imageUrl);
        };
        container.loadMaskImage(settings.maskImageUrl);
        JQmasks.push({
            item: container,
            id: settings.id
        })
        return container;
    };
}(jQuery));

.container {
	background: gold;
  position: relative;
 
}

.container img {
   position:absolute;
   top:0;
   bottom:250px;
   left:0;
   right:0;
   margin:auto;
   z-index:999;
}

.masked-img {
	overflow: hidden;	
	position: relative;
}

.pip {
  display: inline-block;
  margin: 10px 10px 0 0;
}
.remove {
  display: block;
  background: #444;
  border: 1px solid black;
  color: white;
  text-align: center;
  cursor: pointer;
}
.remove:hover {
  background: white;
  color: black;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<input id="fileup" name="fileup" type="file" style="display:none" >

<div class="container">
</div>

Answer 1

实现此目的的最佳方法，您必须禁用和启用 .container div 的点击 pointerevent 试试这个

fileup.onchange = function() {                              
    $('.container').css('pointer-events','none');
}

去除点击功能

$(".remove").click(function(event) {
     $('.container').css('pointer-events','');
});

var target;
var imageUrl = "https://i.imgur.com/RzEm1WK.png";

// Json - it includes mask image 
let jsonData = {
    "layers": [{
        "x": 10,
        "height": 500,
        "layers": [{
            "x": 20,
            "layers": [{
                    "x": 30,
                    "src": "ax0HVTs.png",
                    "y": 31,
                    "name": "mask_1"
                }

            ],
            "y": 21,
            "name": "user_image_1"
        }],
        "y": 11,
        "width": 500,
        "name": "L1"
    }]
};

$(document).ready(function() {

    // upload image onclick mask image

    $('.container').click(function(e) {

        var res = e.target;
        target = res.id;
        console.log(target);
        if (e.target.getContext) {
            // click only inside Non Transparent part
           // $('.container').css('pointer-events','none');
            var pixel = e.target.getContext('2d').getImageData(e.offsetX, e.offsetY, 1, 1).data;
            
            if (pixel[3] === 255) {
                setTimeout(() => {                
                    $('#fileup').click();                    		
                }, 20);
            }
        }
    });

    // Below code will fetch mask image from json file

    function getAllSrc(layers) {
        let arr = [];
        layers.forEach(layer => {
            if (layer.src) {
                arr.push({
                    src: layer.src,
                    x: layer.x,
                    y: layer.y,
                    name: layer.name
                });
            } else if (layer.layers) {
                let newArr = getAllSrc(layer.layers);
                if (newArr.length > 0) {
                    newArr.forEach(({
                        src,
                        x,
                        y,
                        name
                    }) => {
                        arr.push({
                            src,
                            x: (layer.x + x),
                            y: (layer.y + y),
                            name: (name)
                        });
                    });
                }
            }
        });
        return arr;
    }

    function json(data)

    {
        var width = 0;
        var height = 0;

        let arr = getAllSrc(data.layers);

        let layer1 = data.layers;
        width = layer1[0].width;
        height = layer1[0].height;
        let counter = 0;
        let table = [];

        for (let {
                src,
                x,
                y,
                name
            } of arr) {
            $(".container").css('width', width + "px").css('height', height + "px").addClass('temp');
            if (name.indexOf('mask_') !== -1) {
                var imageUrl1 = imageUrl;
            } else {
                var imageUrl1 = '';
            }
            var mask = $(".container").mask({
			// icon  : 
                imageUrl: imageUrl1,
			// Mask image :
                maskImageUrl: 'https://i.imgur.com/' + src,
                onMaskImageCreate: function(img) {

                    // image positions : 

                    img.css({
                        "position": "absolute",
                        "left": x + "px",
                        "top": y + "px"
                    });

                },
                id: counter
            });
            table.push(mask);
            fileup.onchange = function() {
								$('.container').css('pointer-events','none');
                let mask2 = table[target];
                const newImageLoadedId = mask2.loadImage(URL.createObjectURL(fileup.files[0]));
                
                document.getElementById('fileup').value = "";
                //  Remove image

                $("<br/><span id=\"" + newImageLoadedId + "\" class=\"remove\">Remove image</span>").insertAfter("#fileup");

                $(".remove").click(function(event) {
                $('.container').css('pointer-events','');
                    const canvasId = "canvas#" + event.currentTarget.id;
                    // Delete the image
                    const ctx = $("canvas")[event.currentTarget.id].getContext("2d");
                    ctx.fillStyle = "white"
                    ctx.fillRect(0, 0, 500, 500)
                    // Delete the button
                    $(this).remove();                    
                });

                // Remove image code end here....

            };
            counter++;
        }

    }
    json(jsonData);
}); // end of document ready

// upload image & drag code

(function($) {
    var JQmasks = [];
    $.fn.mask = function(options) {
        // This is the easiest way to have default options.
        var settings = $.extend({
            // These are the defaults.
            maskImageUrl: undefined,
            imageUrl: undefined,
            scale: 1,
            id: new Date().getUTCMilliseconds().toString(),
            x: 0, // image start position
            y: 0, // image start position
            onMaskImageCreate: function(div) {},
        }, options);


        var container = $(this);

        let prevX = 0,
            prevY = 0,
            draggable = false,
            img,
            canvas,
            context,
            image,
            timeout,
            initImage = false,
            startX = settings.x,
            startY = settings.y,
            div;

        container.mousePosition = function(event) {
            return {
                x: event.pageX || event.offsetX,
                y: event.pageY || event.offsetY
            };
        }

        container.selected = function(ev) {
            var pos = container.mousePosition(ev);
            var item = $(".masked-img canvas").filter(function() {
                var offset = $(this).offset()
                var x = pos.x - offset.left;
                var y = pos.y - offset.top;
                var d = this.getContext('2d').getImageData(x, y, 1, 1).data;
                return d[0] > 0
            });

            JQmasks.forEach(function(el) {
                var id = item.length > 0 ? $(item).attr("id") : "";
                if (el.id == id)
                    el.item.enable();
                else el.item.disable();
            });
        };

        container.enable = function() {
            draggable = true;
            $(canvas).attr("active", "true");
            div.css({
                "z-index": 2
            });
        }

        container.disable = function() {
            draggable = false;
            $(canvas).attr("active", "false");
            div.css({
                "z-index": 1
            });
        }

        container.updateStyle = function() {
            return new Promise((resolve, reject) => {
                context.beginPath();
                context.globalCompositeOperation = "source-over";
                image = new Image();
                image.setAttribute('crossOrigin', 'anonymous');
                image.src = settings.maskImageUrl;
                image.onload = function() {
                    canvas.width = image.width;
                    canvas.height = image.height;
                    context.drawImage(image, 0, 0, image.width, image.height);
                    div.css({
                        "width": image.width,
                        "height": image.height
                    });
                    resolve();
                };
            });
        };

        function renderInnerImage() {
            img = new Image();
            img.setAttribute('crossOrigin', 'anonymous');
            img.src = settings.imageUrl;
            img.onload = function() {
                settings.x = settings.x == 0 && initImage ? (canvas.width - (img.width * settings.scale)) / 2 : settings.x;
                settings.y = settings.y == 0 && initImage ? (canvas.height - (img.height * settings.scale)) / 2 : settings.y;
                context.globalCompositeOperation = 'source-atop';
                context.drawImage(img, settings.x, settings.y, img.width * settings.scale, img.height * settings.scale);
                initImage = false;
            };
        }

        // change the draggable image

        container.loadImage = function(imageUrl) {
            console.log("load");
            //if (img)
            // img.remove();
            // reset the code.
            settings.y = startY;
            settings.x = startX;
            prevX = prevY = 0;
            settings.imageUrl = imageUrl;
            initImage = true;
            container.updateStyle().then(renderInnerImage);           
            return settings.id;
        };


        // change the masked Image
        container.loadMaskImage = function(imageUrl, from) {
            canvas = document.createElement("canvas");
            context = canvas.getContext('2d');
            canvas.setAttribute("draggable", "true");
            canvas.setAttribute("id", settings.id);
            settings.maskImageUrl = imageUrl;
            div = $("<div/>", {
                "class": "masked-img"
            }).append(canvas);

            // div.find("canvas").on('touchstart mousedown', function(event)
            div.find("canvas").on('dragstart', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.onDragStart(event);
            });

            div.find("canvas").on('touchend mouseup', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.selected(event);
            });

            div.find("canvas").bind("dragover", container.onDragOver);
            container.append(div);
            if (settings.onMaskImageCreate)
                settings.onMaskImageCreate(div);
            container.loadImage(settings.imageUrl);
        };
        container.loadMaskImage(settings.maskImageUrl);
        JQmasks.push({
            item: container,
            id: settings.id
        })
        return container;
    };
}(jQuery));

.container {
	background: gold;
  position: relative;
 
}

.container img {
   position:absolute;
   top:0;
   bottom:250px;
   left:0;
   right:0;
   margin:auto;
   z-index:999;
}

.masked-img {
	overflow: hidden;	
	position: relative;
}

.pip {
  display: inline-block;
  margin: 10px 10px 0 0;
}
.remove {
  display: block;
  background: #444;
  border: 1px solid black;
  color: white;
  text-align: center;
  cursor: pointer;
}
.remove:hover {
  background: white;
  color: black;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<input id="fileup" name="fileup" type="file" style="display:none" >

<div class="container">
</div>